Assuming this was not spontaneous such as a result of a B&E gone bad, it would have to well planned out.
- Did they know the outside cameras were not working? (Or they got lucky.) In one of the pictures of the church on here I thought I saw at least one camera on the roof aimed toward a parking lot. If I saw that, the killer had to have seen it if they planned ahead and, if so, they didn't seem to be concerned about them if they drove there. (And I believe they did.)
- They wore a disguise that covered their face and could even make their body type or gender difficult to determine. They knew about the cameras inside in advance? That means they did a recon some time before. They could have attended a crowded service like Easter when a stranger would be least likely to draw attention.
- They knew Missy's habits or procedures when the weather was bad and she held the workouts inside. When she arrived, where she parked, etc. Unless it was a camper that arrived early on a previous session, they would have parked somewhere to watch. Where? In the lot? That might have drawn Missy's attention. In the gun store down the road with binoculars? I would hope LE looked at videos from that store for as far back as they could for 0400-0500 on the mornings of the sessions. Or did Missy make the details known via a website? I'm inclined to believe that if they planned it they actually drove there sometime in the 2 months prior.
- The killer is walking around and apparently using the hammer or whatever it is while walking through. No indication of stealing. It just seems to me they were waiting and had nervous energy. Maybe just taking some practice swings with the hammer. It doesn't seem like 'professional' hit. They could've been hired, but they possibly had not killed before. I would think an experienced killer would have already made a recon of the building, knew where/how Missy was entering and already have a spot picked out to wait. Preferably some place outside the view of the camera. Break in and get to that spot quickly to minimize time on the video, but they didn't do it that way. I just believe this was either personal to the killer or it was someone 'hired' cheaply to do this. A 'wannabe' hit man - or woman. But not a 'professional' or experienced killer. Like deer hunting - you scout out the woods, find the deer sign and the morning of the hunt you know just you're going to be based on the wind. No walking around aimlessly.
But this is just my take on it. Others may see it differently.